<?php
$url = 'http://www.csdn.net/';
if(file_exists(md5($url)) == false) {
	$content = file_get_contents($url);
	file_put_contents(md5($url), $content);
} else {
	$content = file_get_contents(md5($url));
}


preg_match_all("/<fg>/is", $content,	$matchs);
print_r($matchs);
?>